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Sperm motility describes the ability of sperm to move properly through the female reproductive tract (internal fertilization) or through water (external fertilization) to reach the egg. Sperm motility can also be thought of as the quality , which is a factor in successful conception ; sperm that do not "swim" properly will not reach the egg in ...
Hyperactivation is a type of sperm motility.Hyperactivated sperm motility is characterised by a high amplitude, asymmetrical beating pattern of the sperm tail ().This type of motility may aid in sperm penetration of the zona pellucida, which encloses the ovum.
The sperm present in male fish are immotile while in testes and in seminal fluid, and the fertilization environment determines when the sperm become motile. In salmon, a decrease of potassium in fresh water will initiate the motility of the sperm. A decrease in osmolality after spawning in fresh water makes a cyprinid fish's sperm motile. [23]
A 1992 World Health Organization report described normal human semen as having a volume of 2 mL or greater, pH of 7.2 to 8.0, sperm concentration of 20×10 6 spermatozoa/mL or more, sperm count of 40×10 6 spermatozoa per ejaculate or more, and motility of 50% or more with forward progression (categories a and b) of 25% or more with rapid ...
The sperm and the ovum are known as the gametes (each containing half the genetic information of the parent, created through meiosis). [citation needed] The sperm (being one of approximately 250 million sperm in a typical ejaculation) travels through the vagina and cervix into the uterus or fallopian tubes. Only 1 in 14 million of the ...
Males from India had a 30.3% decline in sperm count, 22.9% decline in sperm motility, and a 51% decrease in morphology over a span of a decade. Doctors in India disclosed that the sperm count of a fertile Indian male had decreased by a third over a span of three decades. [80]
However, multiple mates for a female means each individual male has decreased chances of producing offspring. Sperm competition is an evolutionary pressure on males, and has led to the development of adaptations to increase male's chance of reproductive success. [3] Sperm competition results in a sexual conflict between males and females. [2]
Anisogamy is the form of sexual reproduction that involves the union or fusion of two gametes which differ in size and/or form. [12] The smaller gamete is considered to be male (a sperm cell), whereas the larger gamete is regarded as female (typically an egg cell, if non-motile).